1. Field of the Invention
This invention relates to a zoom lens system, and more particularly to a small-sized zoom lens system consisting of three groups.
2. Background of the Invention
Recently, in the field of the compact camera, a small-sized and inexpensive zoom lens system has been demanded. Particularly, in the contents of the inexpensive factors, there are included limited number of parts, easy assembling and so forth. For this purpose, it has been designed to minimize the number of lenses constituting in the zoom lenses.
Heretofore, the conventional zoom lens systems having the smallest number of constituting lenses, there is already a zoom lens consisting of two groups and including three glass lenses. In these zoom lens systems, a first group consists of a concave lens and a convex lens, and a second group consists of a concave lens.
Now, in order to make the zoom lens systems small-sized, there is required not only the reduction of the number of parts but also the small movement values of the lenses from the wide end to the telescopic end.
In the case of the conventional zoom lens system consisting of the two groups, such a problem has been presented that the movement value of the lens during the zooming is large, so that small size of the lens cannot be satisfactorily achieved.